• Prior to his elevation to deputy, he served for about three years as under secretary of defense for acquisition, technology and logistics, where he was in charge of technology and weapons-buying.

• Under President Clinton, Carter served as assistant secretary of defense for international security policy, where he helped secure nuclear weapons in Eastern Europe following the collapse of the Soviet Union and played a role in the oversight of the US nuclear arsenal.

• Carter has a long list of academic credentials, having earned his bachelors in physics and medieval history from Yale and doctorate in theoretical physics from Oxford University, where he was also a Rhodes Scholar.

• Carter is a longtime lecturer at Harvard University and former head of the Belfer Center for Science and International Security at Harvard’s Kennedy School of Government. He was also a former research fellow at MIT, where he wrote a paper finding the Reagan administration’s “Star Wars” initiative “not technically feasible.”